System and method for gaming

ABSTRACT

A method of gaming comprises providing an additional game that operates independently of a main game. The outcome of the additional game operates to vary a subset of symbols in the main game responsive to a variance criterion being met, to thereby affect the game outcome in the main game.

RELATED APPLICATIONS

This application claims priority to United States ProvisionalApplication No. 61/057654 having a filing date of May 30, 2008, which isincorporated herein by reference in its entirety.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[Not Applicable]

MICROFICHE/COPYRIGHT REFERENCE

[Not Applicable]

BACKGROUND OF THE INVENTION

The present invention relates to a gaming system, a method of gaming, agame controller and computer program code.

It is known to provide a gaming system which comprises a game controllerarranged to randomly display several symbols from a predetermined set ofsymbols and to determine a game outcome such as a game win based on thedisplayed symbols. Such gaming systems may commonly be implemented as astepper machine provided with reels with each reel carrying severalsymbols of the set, or a video machine wherein selected symbols aredisplayed on virtual reels on a video display.

It is also known to provide a “WILD” symbol. A “WILD” symbol is a symbolwhich can substitute for any other symbol. For example, if a playerrequires five (5) “KING” symbols to form a winning combination, then acombination of four (4) KING symbols and one (1) WILD symbol also formsa winning combination, because the WILD symbol operates to “substitutefor” (i.e. is equivalent to) the KING symbol.

In other words, the player perceives the WILD symbol as being a symbolthat provides the player with an “extra chance” to receive a favorablegame outcome (a win). While the use of WILD symbols is one feature usedto gain and maintain player interest, there is a need to find new anddifferent ways to capture and maintain player interest.

BRIEF SUMMARY OF THE INVENTION

In a first aspect, the invention provides a method of gaming comprisingproviding an additional game that operates independently of a main game,wherein the outcome of the additional game operates to vary a sub-set ofsymbols in the main game responsive to a variance criterion being met,to thereby affect a game outcome in the main game.

The game outcome in turn may affect the probability of a prize beingawarded. That is, the game outcome is compared against prize data todetermine whether a prize is due to a player.

In an embodiment, the variance criterion is that a symbol displayed inthe additional game is also displayed in the main game.

In an embodiment, the variance criterion is that an amount wagered inthe main game meets or exceeds a specified wager amount. The variancecriterion may alternatively be that an ante bet has been wagered in themain game to thereby activate the additional game.

In one embodiment, the outcome of the additional game is at least onesymbol that operates to transform like symbols displayed in the maingame to another symbol, so as to affect an outcome of the main game. Thelike symbol(s) may, for example, be transformed into substitute or“WILD” symbols.

In an embodiment, the symbol(s) displayed in the additional game is/arerandomly selected from a subset of symbols displayable in the main game.

In an embodiment, the total number of each type of symbol available forselection in the additional game may be a function of a bet amountselected in the main game. Alternatively, a combination of the type ofsymbol and the total number of symbols may be utilized.

The additional game may be played at the conclusion of the main game,prior to commencement of the main game, or during the main game.

In an embodiment, the symbol(s) in the additional game are displayed ina reel format.

In a second aspect, the invention provides a game controller for agaming system, the game controller arranged to provide an additionalgame that operates independently of a main game, wherein the outcome ofthe additional game operates to vary a sub-set of symbols in the maingame responsive to a variance criterion being met, to thereby affect agame outcome in the main game.

In an embodiment, the variance criterion is that a symbol displayed inthe additional game is also displayed in the main game.

In an embodiment, the variance criterion is that an amount wagered inthe main game meets or exceeds a specified wager amount. The variancecriterion may alternatively be that an ante bet has been wagered in themain game, to thereby activate the additional game.

In an embodiment, symbols displayed in the main game which correspond tosymbols displayed in the additional game are transformed into asubstitute or “WILD” symbol.

In an embodiment, the symbol(s) displayed in the additional game is/arerandomly selected from a subset of symbols displayable in the main game.

In an embodiment, the total number of each type of symbol available forselection in the additional game may be a function of an amount wageredin the main game. Alternatively, a combination of the type of symbol andthe total number of symbols may be utilized.

The additional game may be played at the conclusion of the main game,prior to commencement of the main game, or during the main game.

In an embodiment, the symbol(s) selected for display in the additionalgame are displayed in a reel format.

In an embodiment, the controller includes a display module operable tocause a representation of the main game and additional game to bedisplayed on a gaming terminal.

In accordance with a third aspect of the present invention, there isprovided a gaming system comprising a game controller arranged tocontrol play of a main game and an additional game that operatesindependently of the main game, such that an outcome of the additionalgame operates to vary a subset of symbols displayed in the main gameresponsive to a variance criterion being met, to thereby affect anoutcome of the main game; and a display operable to display arepresentation of the main game and additional game.

In a fourth aspect, the invention provides computer program code whichwhen executed by a processor implements a method in accordance with thefirst aspect of the invention.

In a fifth aspect the invention provides a computer readable mediumcomprising the program code in accordance with a fourth aspect of theinvention.

In accordance with a sixth aspect the present invention comprisestransmitting or receiving a data signal comprising the computer programcode in accordance with the fourth aspect.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

A preferred embodiment of the invention will now be described inrelation to the following drawings in which:

FIG. 1 is a block diagram of the core components of a gaming system;

FIG. 2 is a perspective view of a gaming machine;

FIG. 3 is a block diagram of the functional components of a gamingmachine;

FIG. 4 is a block diagram representing the structure of a memory;

FIG. 5 is a diagram schematic of a networked gaming system;

FIG. 6 is a further block diagram of the gaming system;

FIG. 7 is a flowchart of a method in accordance with an embodiment ofthe invention; and

FIGS. 8 a, 8 b and 8 c are diagrams depicting examples of a reel-typegame in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention provides a gaming systemimplementing a main game and an additional game. The additional gameoperates independently of the main game but has the effect of varying asub-set of symbols in the main game in response to a variance criteriabeing met, to thereby effect the outcome of the main game. The variancecriteria may, for example, be that a symbol displayed in the additionalgame corresponds to a symbol displayed in the main game, such that thecorresponding symbol in the main game is transformed into another symbolsuch as a substitute or “WILD” symbol.

The gaming system may be provided in a number of different forms.

In a first form, a stand alone gaming machine is provided wherein all ormost components required for implementing the game are present in aplayer operable gaming machine.

In a second form, a distributed architecture is provided wherein some ofthe components required for implementing the game are present in aplayer operable gaming machine and some of the components required forimplementing the game are located remotely relative to the gamingmachine. For example, a “thick client” architecture may be used whereinpart of the game is executed on a player operable gaming machine andpart of the game is executed remotely, such as by a gaming server; or a“thin client” architecture may be used wherein most of the game isexecuted remotely such as by a gaming server and a player operablegaming machine is used only to display audible and/or visible gaminginformation to the player and receive gaming inputs from the player.

However, it will be understood that other arrangements are envisaged.For example, an architecture may be provided wherein a gaming machine isnetworked to a gaming server and the respective functions of the gamingmachine and the gaming server are selectively modifiable. For example,the gaming system may operate in stand alone gaming machine mode, “thickclient” mode or “thin client” mode depending on the game being played,operating conditions, and so on. Other variations will be apparent topersons skilled in the art.

Irrespective of the form, the gaming system comprises several corecomponents. At the broadest level, the core components are a playerinterface 50 and a game controller 60 as illustrated in FIG. 1. Theplayer interface is arranged to enable manual interaction between aplayer and the gaming system and for this purpose includes theinput/output components required for the player to enter instructionsand play the game.

Components of the player interface may vary from embodiment toembodiment but will typically include a credit mechanism 52 to enable aplayer to input credits and receive payouts, one or more displays 54 anda game play mechanism 56 that enables a player to input game playinstructions.

The game controller 60 is in data communication with the playerinterface and typically includes a processor 62 that processes the gameplay instructions in accordance with game play rules and outputs gameplay outcomes to the display. Typically, the game play instructions arestored as program code in a memory 64 but can also be hardwired. Hereinthe term “processor” is used to refer generically to any device that canprocess game play instructions in accordance with game play rules andmay include: a microprocessor, microcontroller, programmable logicdevice or other computational device, a general purpose computer (e.g. aPC) or a server.

A gaming system in the form of a stand alone gaming machine 10 isillustrated in FIG. 2. The gaming machine 10 includes a console 12having a display 14 on which is displayed representations of a game 16that can be played by a player. A mid-trim 20 of the gaming machine 10houses a bank of buttons 22 for enabling a player to interact with thegaming machine, in particular during game play. The mid-trim 20 alsohouses a credit input mechanism 24 which in this example includes a coininput chute 24A and a bill collector 24B. Other credit input mechanismsmay also be employed, for example, a card reader for reading a smartcard, debit card or credit card. A player marketing module may beprovided having a reading device may also be provided for the purpose ofreading a player tracking device, for example as part of a loyaltyprogram. The player tracking device may be in the form of a card, flashdrive or any other portable storage medium capable of being read by thereading device.

A top box 26 may carry artwork 28, including for example pay tables anddetails of bonus awards and other information or images relating to thegame. Further artwork and/or information may be provided on a frontpanel 29 of the console 12. A coin tray 30 is mounted beneath the frontpanel 29 for dispensing cash payouts from the gaming machine 10.

The display 14 shown in FIG. 2 is in the form of a video display unit,particularly a cathode ray tube screen device. Alternatively, thedisplay 14 may be a liquid crystal display, plasma screen, any othersuitable video display unit, or the visible portion of anelectromechanical device. The top box 26 may also include a display, forexample a video display unit, which may be of the same type as thedisplay 14, or of a different type.

FIG. 3 shows a block diagram of operative components of a typical gamingmachine which may be the same as or different to the gaming machine ofFIG. 2.

The gaming machine 100 includes a game controller 101 having a processor102. Instructions and data to control operation of the processor 102 arestored in a memory 103, which is in data communication with theprocessor 102. Typically, the gaming machine 100 will include bothvolatile and non-volatile memory and more than one of each type ofmemory, with such memories being collectively represented by the memory103.

The gaming machine has hardware meters 104 for purposes includingensuring regulatory compliance and monitoring player credit, aninput/output (I/O) interface 105 for communicating with peripheraldevices of the gaming machine 100. The input/output interface 105 and/orthe peripheral devices may be intelligent devices with their own memoryfor storing associated instructions and data for use with theinput/output interface or the peripheral devices. A random numbergenerator module 113 generates random numbers for use by the processor102. Persons skilled in the art will appreciate that the reference torandom numbers includes pseudo-random numbers.

In the example shown in FIG. 3, a player interface 120 includesperipheral devices that communicate with the game controller 101comprise one or more displays 106, a touch screen and/or buttons 107, acard and/or ticket reader 108, a printer 109, a bill acceptor and/orcoin input mechanism 110 and a coin output mechanism 111. Additionalhardware may be included as part of the gaming machine 100, or hardwaremay be omitted as required for the specific implementation.

In addition, the gaming machine 100 may include a communicationsinterface, for example a network card 112. The network card may, forexample, send status information, accounting information or otherinformation to a central controller, server or database and receive dataor commands from the central controller, server or database.

FIG. 4 shows a block diagram of the main components of an exemplarymemory 103. The memory 103 includes RAM 103A, EPROM 103B and a massstorage device 103C. The RAM 103A typically temporarily holds programfiles for execution by the processor 102 and related data. The EPROM103B may be a boot ROM device and/or may contain some system or gamerelated code. The mass storage device 103C is typically used to storegame programs, the integrity of which may be verified and/orauthenticated by the processor 102 using protected code from the EPROM103B or elsewhere.

It is also possible for the operative components of the gaming machine100 to be distributed, for example input/output devices106,107,108,109,110,111 to be provided remotely from the game controller101.

FIG. 5 shows a gaming system 200 in accordance with an alternativeembodiment. The gaming system 200 includes a network 201, which forexample may be an Ethernet network. Gaming machines 202, shown arrangedin three banks 203 of two gaming machines 202 in FIG. 5, are connectedto the network 201. The gaming machines 202 provide a player operableinterface and may be the same as the gaming machines 10,100 shown inFIGS. 2 and 3, or may have simplified functionality depending on therequirements for implementing game play. While banks 203 of two gamingmachines are illustrated in FIG. 5, banks of one, three or more gamingmachines are also envisaged.

One or more displays 204 may also be connected to the network 201. Thedisplays 204 may, for example, be associated with one or more banks 203of gaming machines. The displays 204 may be used to displayrepresentations associated with game play on the gaming machines 202,and/or used to display other representations, for example promotional orinformational material.

In a thick client embodiment, game server 205 implements part of thegame played by a player using a gaming machine 202 and the gamingmachine 202 implements part of the game. With this embodiment, as boththe game server and the gaming device implement part of the game, theycollectively provide a game controller. A database management server 206may manage storage of game programs and associated data for downloadingor access by the gaming devices 202 in a database 206A. Typically, ifthe gaming system enables players to participate in a Jackpot game, aJackpot server 207 will be provided to carry out the accounting inrespect of the Jackpot game. A loyalty program server 212 may also beprovided.

In a thin client embodiment, game server 205 implements most or all ofthe game played by a player using a gaming machine 202 and the gamingmachine 202 essentially provides only the player interface. With thisembodiment, the game server 205 provides the game controller. The gamingmachine will receive player instructions, pass these to the game serverwhich will process them and return game play outcomes to the gamingmachine for display. In a thin client embodiment, the gaming machinescould be computer terminals, e.g. PCs running software that provides aplayer interface operable using standard computer input and outputcomponents.

Servers are also typically provided to assist in the administration ofthe gaming network 200, including for example a gaming floor managementserver 208, and a licensing server 209 to monitor the use of licensesrelating to particular games. An administrator terminal 210 is providedto allow an administrator to run the network 201 and the devicesconnected to the network.

The gaming network 200 may communicate with other gaming systems, otherlocal networks, for example a corporate network, and/or a wide areanetwork such as the Internet, for example through a firewall 211.

Persons skilled in the art will appreciate that in accordance with knowntechniques, functionality at the server side of the network may bedistributed over a plurality of different computers. For example,elements may be run as a single “engine” on one server or a separateserver may be provided. For example, the game server 205 could run arandom generator engine. Alternatively, a separate random numbergenerator server could be provided. Further, persons skilled in the artwill appreciate that a plurality of games servers could be provided torun different games or a single game server may run a plurality ofdifferent games as required by the terminals.

In some implementations the game controllers of such gaming machinesselect symbols by employing a stop determining function that randomlydetermines the stop position for each reel. For example, if there arefive reels, each having twenty symbols, the stop determining functionmight determine that the stop positions are positions: 3, 13, 7, 9 and17. The spinning of the reels is then controlled so that each symbolcomes to a stop in the same row, typically a predetermined row in a“window” visible to the player on the display that which corresponds toa player playing a single win line. When a reel stops, the symbols willbe in one of a plurality of possible symbol positions for that reelrelative to the stop position.

Spinning reel type games typically allow a player to select how many winlines of a plurality of win lines they will play in each game—i.e. aminimum of one win line up to the maximum number of win lines allowed bythe game. Persons, skilled in the art, will appreciate that in otherembodiments, the player may select a number of reels to play. Each winline is formed by a set of symbol positions consisting of one symbolposition from each reel. That is, a predetermined symbol position ofeach reel is assigned to a win line. The symbol positions thatconstitute each of the win lines are usually advertised to the player bymarkings on the display or diagrams showing the symbol positions thatcorrespond to each win line. Some of the win lines will be horizontal ordiagonal lines but others may be more complex combinations of symbols.Typically, the win lines will be constituted by symbol positions in thevisible window. A game outcome is determined based on the symbols on thewin lines and a prize table that specifies awards.

Further Details of the Game Controller

The game controller 60 of the preferred embodiment (as previouslydescribed with reference to FIG. 1) is shown in more detail in FIG. 6.It will be apparent that the processor 62 implements a number ofmodules, namely random number generator module 621, symbol selectormodule 622, outcome determiner module 623, award determiner module 624,sequence monitoring module 625, and display controller module 626 basedon data stored in memory 64. Persons skilled in the art will appreciatethat not all modules need be implemented by processor 62. For example,the random number generator module 621 could be implemented by aseparate circuit, or by a random number generator server.

In the presently described embodiment, the game controller 60 isoperable to control play of both a main game in the form of a reel game,and an additional, or supplementary, game which operates independentlyof the main reel game. The additional game has the effect of varying theoutcome of the main game responsive to a variance criterion being met,as will be described in more detail in subsequent paragraphs.

Operation of the main game will first be described with reference toFIG. 8 a. In accordance with the presently described embodiment, themain game is in the form of a reel game. A player places an initialwager which causes a plurality of reels to spin. The symbols which aredisplayed on the reels after they have come to rest (i.e. are displayedin the reel window) are selected by the symbol selector 622, based onsymbol data 641 which specifies the available symbols. The displayedsymbols (generated utilizing the display 54) are rendered utilizingimage data 642. The symbols are selected by the symbol selector 622using a random number obtained from the random number generator 621. Theoutcome determiner module 623 determines game outcomes and theirassociated prizes based on the number of win lines the player is playingand the symbol combinations appearing in the reel window. The value ofany prizes awarded to the player is determined utilizing the gameoutcomes and prize data 643. Persons skilled in the art will alsoappreciate that the game outcomes and their associated prizes aredisplayed on the display 54, which is controlled, at least in part, bythe display controller 626.

An award determiner 624 is employed to keep track of the total award andsubsequently to modify the award as more games are played. The total ismaintained as total data 644 in memory 64. Thus, after each game theaward determiner 624 updates the total data 644 to reflect the currenttotal. The sequence monitor 625 monitors for completion of the sequenceand, at the conclusion of the sequence, instructs the award determiner624 to modify the accumulated total.

With reference to FIG. 8 b, the additional game is in the form of asubstitute reel 806. The substitute reel 806 is controlled by a WILDsubstitute reel module 627 implemented by the game controller 60. In theembodiment described herein, the reel module 627 controls the reel 806such that it spins independently of the reels displayed in the maingame.

That is, an additional reel 806, hereinafter referred to as the “sixthreel” (due to the embodiment having a main reel game including fivereels) is provided in addition to the main reel game of a gamingmachine. In the embodiment, the sixth reel 806 is displayed alongsidethe reel window 800 of the main game. However, it will be understoodthat the sixth reel 806 may be displayed in any suitable location, suchas, for example, on a video screen above the main reel game. Moreover,the sixth reel 806 may be displayed in any suitable configuration, suchas a “vertical” reel, a “horizontal” reel, or as a “wheel” (i.e. a wheelakin to a roulette wheel).

In another embodiment, the sixth reel 806 may be remotely displayed(e.g. the sixth reel 806 may be implemented as a roulette-style wheelwhich is located adjacent to, but not incorporated into, the gamingmachine). Such variations are within the purview of a person skilled inthe art.

In the presently described embodiment, the sixth reel includes a set ofsymbols that are a sub-set of the symbols available for selection (i.e.by the symbol selector 622) in the main reel game. The set of symbolsavailable for selection and display in the sixth reel game is stored inmemory 64 as supplementary symbol data 645.

It will be understood that the sixth reel 806 may include anycombination of a sub-set of symbols available for selection in the mainreel game, or indeed the entire set of symbols displayable in the mainreel game. Moreover, the sixth reel may also include other symbols(hereafter “supplementary symbols”) not available in the main reel game.For example, the supplementary symbols may include “blank” symbols (i.e.certain spaces on the reel contain no symbol), or alternatively, thesixth reel may provide supplementary symbols which award “instant”prizes, such as a feature game, a jackpot, etc. Such variations arewithin the purview of a person skilled in the art.

The operation of the sixth reel is described with reference to theflowchart of FIG. 7.

In the embodiment described herein, the spinning of the sixth reel 806takes place after the reels of the main game have come to a stop. Thatis, referring to flowchart 700 of FIG. 7, a player initiates the mainreel game (702). The player is informed of the outcome of the main reelgame, and if an award is due to the player, the player is also informedof the award that the player has won as a result of the outcome in themain reel game (704). The sixth reel is then spun, and a substitutesymbol is revealed in the centre position 808 of the sixth reel (706).The substitute symbol revealed in the centre position 808 operates tovary the outcome of the main game provided that a variance criterion hasbeen met. In the presently described embodiment, the variance criterionis that a like symbol appears in the reel window 800 of the main game(708).

That is, if the substitute symbol revealed in the centre position 808 ofthe sixth reel (i.e. the symbol that operates to substitute for the WILDsymbol) appears in the initial main game, then each symbol in the maingame that accords with the substitute symbol is transformed to a WILDsymbol (710). Once the transformation is finalized, the final gameoutcome is shown to the player, and the award determiner 624recalculates any awards due to the player (712).

A specific example will now be described with reference to the screenshots shown in FIGS. 8 a, 8 b and 8 c. At FIG. 8 a, there is shown aconventional 3×5 (15 element) reel game 800. Each of the verticalcolumns of elements represent a “reel”, with each element in each reelbeing arranged to display a symbol. In the example, the symbols usedcorrespond with the symbols used on a conventional deck of cards (i.e.the numerals 2-9, and the symbols J, Q, K and A). The symbol set alsoincludes a WILD symbol, which operates to substitute for any one of theother symbols. In this example, it is assumed that a player must receiveat least three (3) identical symbols in any one row (horizontal) to beawarded a prize. Although it will be understood by persons skilled inthe art that any prize winning combination could equally apply dependingonly on the desired implementation.

At FIG. 8 a, a player has initiated a game (e.g. by placing a wager andselecting a number of pay lines to play), and an initial game outcome isdisplayed in the main reel game. As can be seen, the “K” (King) symbolappears twice in the centre row (802), and the “Q” (Queen) symbol alsoappears twice in the centre row (804). In the initial game outcome, theplayer has not won any awards or prizes, as there is no combinationdisplayed that would result in an award.

At FIG. 8 b, there is shown a sixth reel 806, which automatically spinswhen the reel spin of the main game has concluded. On the sixth reel 806coming to rest, a symbol 808 is displayed in the centre position. Inthis instance, the symbol displayed in the centre position 808 is a “Q”(Queen) symbol. Therefore, the “Q” Queen symbol substitutes for the WILDsymbol in the main game.

As such, the gaming system operates to change all “Q” (Queen) symbols inthe main game to WILD symbols, resulting in the varied reel window shownin FIG. 8 c. As the final game outcome is now different from the initialgame outcome, the award due to the player is recalculated.

According to FIG. 8 c, it can be seen that by changing the two “Q”symbols in the main game to WILD symbols, a winning combination of four“K” (King) symbols is formed (810), as the WILD symbols (which havesubstituted for the “Q” (Queen) symbols) operate to substitute for the“K” King symbol. As such, the final game outcome has been varied and asa result an award is now payable to the player.

In the embodiment described herein, the sixth reel is spun at theconclusion of every main reel game. However, it will be understood thatthe sixth reel may be arranged to only spin as required. For example,the sixth reel may only spin at random times, or in response to aparticular game outcome in the main reel game.

Moreover, in an alternate embodiment, the sixth reel may spin before orduring the initial game. That is, the player may be notified of theidentity of the WILD symbol before or at the same time as the main gameresult is displayed.

Optionally, the type of symbols and/or the number of times a particulartype of symbol appears on the sixth reel may be determined by the betamount placed by the player during the main reel game. In accordancewith such an embodiment, the probability of symbols displayed in themain game being substituted for a WILD symbol (thereby increasing theprobability of being awarded a prize) may be a function of the betplaced by the player during the main reel game. That is, the higher thebet placed by the player, the higher the probability of the WILDsubstitute symbol being the “necessary” substitute symbol to vary thegame outcome in a manner that results in a player receiving an award.

In one example implementation, the probability may be increased byincreasing the number of symbols of a particular type on the reel, suchthat the probability of receiving the most advantageous WILD substitutesymbol is increased. By increasing the number of available symbols of aparticular type, the probability of a player receiving the most desiredsymbols is correspondingly increased. Of course, it will be understoodthat any suitable technique or formula may be utilized to increase theprobability of a player receiving a desired WILD substitute symbol (andtherefore an additional prize or award). For example, one such techniquemay be to increase the number of symbols displayed in the sixth reelspin, which in turn increases the likelihood of a corresponding symbolbeing displayed in the main reel game. Various other techniques would beknown to a person skilled in the art.

It will be understood that determining the type of symbols that appearon the sixth reel game as a function of the initial bet may be usedseparately or in conjunction with other incentive mechanisms, as desiredby the game operator. Such variations are within the purview of a personskilled in the art.

As described above, the sixth reel may also include blank symbols. Blanksymbols result in no symbols in the main game becoming WILD symbols(i.e. a blank symbol has no effect on the result of the main game).

An alternative embodiment to that previously described, may involve theplayer placing an ante bet during play of the main game in order toallow the additional game to become operational. Equally, the player maybe required to wager more than a designated amount in the main game forthe additional game to operate.

The embodiments described herein advantageously increase player interestand involvement in the game, as the player is aware that they have a“second chance” to affect the game outcome and be awarded a prize, eventhough they may not have won a prize in the main game.

Many gaming systems, such as the exemplary gaming system describedherein, implement games that involve a display of spinning reels as partof the display of the outcome of a game. However, persons skilled in theart will appreciate that the invention broadly described herein can beimplemented in respect of other forms of games, including card games,ball draw games (e.g. bingo or keno), dice games, and pin and ballgames. For example, rather than providing a reel with a number ofsymbols, a “deck of cards” may be provided, such that each card equatesto a symbol in the main reel game. A person skilled in the art wouldunderstand that such a concept may also be easily extended to dicegames, numbered ball games, or indeed any type of game of chance wheremarkers with different values/symbols are utilized.

1. A method of gaming comprising: providing an additional game thatoperates independently of a main game, wherein the outcome of theadditional game operates to vary a sub-set of symbols in the main gameresponsive to a variance criterion being met, to thereby affect the gameoutcome in the main game.
 2. A method in accordance with claim 1,wherein on the game outcome being varied, the game outcome is checkedagainst prize data to determine whether a prize is due to a player.
 3. Amethod in accordance with claim 1, wherein the variance criterion isthat a symbol displayed in the additional game is also displayed in themain game.
 4. A method in accordance with claim 1, wherein the variancecriterion is that an amount wagered in the main game meets or exceeds aspecified wager amount.
 5. A method in accordance with claim 1, whereinthe variance criterion is that an ante bet has been wagered in the maingame to thereby activate the additional game.
 6. A method in accordancewith claim 1, wherein the outcome of the additional game is at least onesymbol that operates to transform like symbols displayed in the maingame to another symbol.
 7. A method in accordance with claim 6, whereinlike symbols are transformed into a substitute or “WILD” symbol.
 8. Amethod in accordance with claim 1, wherein the symbol(s) displayed inthe additional game is/are randomly selected from a subset of symbolsdisplayable in the main game.
 9. A method in accordance with claim 1,wherein the total number of each type of symbol available for selectionin the additional game is a function of a bet amount selected in themain game.
 10. A method in accordance with claim 1, wherein theadditional game is played either at the conclusion of the main game,prior to commencement of the main game, or during the main game.
 11. Amethod in accordance with claim 1, wherein the symbol(s) in theadditional game are displayed in a reel format.
 12. A game controllerfor a gaming system, the game controller arranged to: provide anadditional game in addition to a main game, the additional gameoperating independently of the main game, wherein the outcome of theadditional game operates to vary a sub-set of symbols in the main game,to thereby affect the probability of a prize being awarded.
 13. A gamecontroller in accordance with claim 12, wherein the variance criterionis that a symbol displayed in the additional game is also displayed inthe main game.
 14. A game controller in accordance with claim 12,wherein the variance criterion is that an amount wagered in the maingame meets or exceeds a specified wager amount.
 15. A game controller inaccordance with claim 12, wherein the variance criterion is that an antebet has been wagered in the main game to thereby activate the additionalgame.
 16. A game controller in accordance with claim 12, wherein theoutcome of the additional game is at least one symbol that operates totransform like symbols displayed in the main game to another symbol. 17.A game controller in accordance with claim 16, wherein like symbols aretransformed into a substitute or “WILD” symbol.
 18. A game controller asclaimed in claim 12, further comprising a symbol selector arranged torandomly select symbols for displaying in the additional game, from asubset of symbols displayable in the main game.
 19. A game controller inaccordance with claim 12, wherein the total number of each type ofsymbol available for selection by the symbol selector is a function of abet amount selected in the main game.
 20. A game controller inaccordance with claim 12, wherein the additional game is played eitherat the conclusion of the main game, prior to commencement of the maingame, or during the main game.
 21. A game controller in accordance withclaim 12, further comprising a display module arranged to display thesymbol(s) in the additional game in a reel format.
 22. A game controllerin accordance with claim 21, wherein the display module is operable tocause a representation of the main game and the additional game to bedisplayed on a gaming machine.
 23. A gaming system comprising: a modulearranged to control play of a main game and an additional game operatingindependently of the main game, such that an outcome of the additionalgame operates to vary a sub-set of symbols in the main game responsiveto a predetermined criterion being met, to thereby affect theprobability of a prize being awarded; and a display module operable todisplay a representation of the main game and additional game on agaming machine.
 24. A method in accordance with claim 1, furthercomprising executing a computer program code by a processor.
 25. Amethod in accordance with claim 24, further comprising storing in acomputer readable medium said computer program code.
 26. A method inaccordance with claim 24, further comprising transmitting or receivingsaid computer program code.